The dynamic damage and fracture of metallic materials under extreme conditions represent critical issues of significant concern in national defense engineering fields such as high-speed impact, inertial confinement fusion, and implosion compression. Under prolonged irradiation environments, the formation of numerous nanoscale helium bubbles through cascade damage becomes a distinctive microstructural characteristic of irradiated metallic materials. Understanding how such microstructural evolution influences material failure behaviors under intense dynamic loadings has emerged as a pivotal scientific question. This report presents the authors' recent theoretical research progress on the dynamic damage and fracture of metals containing helium bubbles under extreme conditions. Molecular dynamics simulations reveal that the expansion-coalescence of helium bubbles constitutes a novel physical mechanism governing the damage fracture of irradiated metals during dynamic tensile process. Notably, the expansion of helium bubbles exhibits significant inhibition effects on void nucleation-growth, leading to fundamental alteration in the damage failure mechanism of irradiated metals. Furthermore, systematic investigations have been conducted on the effects of strain rate, pressure, temperature, helium bubble concentration, and grain boundaries on the damage fracture of irradiated metals, elucidating the competitive and cooperative interplay between helium bubbles and voids under various conditions. Based upon the classical void growth model, a dynamic damage theoretical model incorporating helium bubble effect has been developed and implemented into hydrodynamic simulation codes, yielding computational results consistent with experimental observations.

dynamic damage,irradiation metals,helium bubbles,extreme conditions